The overwhelming majority of jobs in the technology industry do not go to people who cold apply via jobs pages. This is important for you to know and operationalize. A little off topic, but why is this? I don't doubt what he is saying but why is it not good enough to apply for a job via standard channels and not have to be in "the boys club" ?
At the highest level of abstraction, practitioners in different tribes do the same job, but the way other tribes do things might be unrecognizable and/or horrifying from your perspective.
You want to hire from your tribe. Buzzwords get picked up by people who don't really mean them in their original sense (see: enterprises doing waterfall and calling it agile) so buzzwords on resumes don't identify tribe, and an interview is only a few hours of a candidate in a contrived high-pressure situation where they're nervous/presenting the mask they think you want to see.
So you start with people you personally know to be in your tribe. When those run out, you realize you can trust the people you personally know to identify other tribe members, and this works up to the nth degree. If that's not enough, you learn that certain institutions (employers, universities, etc.) select, demand, or instill membership in your tribe, so you go looking for candidates who have been attached to these institutions first.
FWIW this is not unique to software by any means. I worked on the tech side of theater in college and have friends now working in that industry. Designers, stage and production managers, etc. in the real world are hired almost exclusively on reputation and recommendation. They are cold-emailed job offers (not ads to come compete for a job, but actual work) based on colleagues' experiences with them at previous gigs. Gigs often last only a few weeks, so you are playing this game constantly. You essentially cannot break in as a total outsider. You need to go to a school that is trusted to provide good interns (because its teachers are from the right tribe and it runs its student productions the right way), and impress at your internship, or else know someone who will convince their boss to take a chance on you. Sometimes hiring does have a formal application process, but you are not getting the job unless someone reading the application has heard of you or has a lot of respect for one of the institutions on your resume.
"The boys club" is a (flawed) attempt at instituting meritocracy by a system of recursive trust. I believe it's much better than the resume and interview dance, but I'd still love for software to discover its "blind audition" hiring technique.